1. Field of the Invention
The present invention generally relates to an optical fiber structure, and more particularly, to an optical fiber structure with a filtering thin film.
2. Description of Related Art
The currently available optical fiber component goods, such as fiber polarizer having a reflective component with an fiber Bragg grating (FBG) for selecting wavelength or a protector for pumping light source, have disadvantage of expensive price and fabrication difficulty.
Among the related traditional technologies, for example, the one disclosed by U.S. Pat. No. 6,832,025 is based on that an optical gritting with a long cycle period is disposed between the fiber core and the fiber cladding layer of an optical fiber so as to produce a light-filtering effect with the fiber. However, the fiber engineered and fabricated with the above-mentioned approach is easily affected by thermal effect, causing wavelength drifted. In addition, the above-mentioned fiber component is disadvantageous in easily being damaged, inability of being bent and expensive price.
Among the other traditional technologies, the one, for example, disclosed by U.S. Pat. No. 7,440,653 is based on that by using interference fringes generated by laser light interference, differences of the refractive index in the fiber core are established; the differences of the refractive index further are used to form an optical gritting for selecting the wavelength of the laser light through screening. The fiber provided by U.S. Pat. No. 7,440,653 has the same disadvantage as the above-mentioned one that it is likely thermally effected to thereby make wavelength drifted, easily damaged, inability to be bent and expensive.
Confronting the above-mentioned situation, the related manufactures are making efforts to develop a simpler fabrication, which is applicable in at least the individual passive components in a fiber so as to reduce the cost.